Hacker who made ATMs spit out cash and was set to deliver a talk about hacking pacemakers and many wireless implantable medical devices has died in San Francisco.

Real cause of Barnaby Jack death is still unknown, he died at his in San Francisco and authorities are still investigating the real cause of his death.

San Francisco Deputy Coroner Kris Barbrich said.

Jack, who was in his mid-30s, was scheduled to speak on August 1 at the Black Hat security conference in Las Vegas. The headline of his talk was, "Implantable Medical Devices: Hacking Humans," according to a synopsis on the Black Hat conference website.

Jack made headlines at the Black Hat conference in 2010 when he demonstrated, his ability to hack stand-alone ATMs. He was able to hack them in two ways - remotely and using physical keys that come with the machines

He had spent years tinkering with ATMs he bought online and found that the keys that came with his machines were the same for all ATMs of that type made by that manufacturer. He used his key to unlock a compartment in the ATM, and then used a USB slot to insert a program that commanded the ATM to dump its vaults.